1. Field of the Invention
The present invention relates to a novel process for producing anthrone which is useful as intermediates for dyes, photosensitizers, analytical reagents and other organic compounds. The anthrone is especially useful as intermediates for benzanthrone derivatives as dyes.
2. Description of the Prior Arts
Anthrone has been produced by reducing anthraquinone with a mineral acid and a metal such as copper, aluminum, iron, zinc or tin. For example, it has been known that anthrone is produced by reducing anthraquinone with tin and hydrochloric acid in about 7 times of acetic acid in "Organic Syntheses Vol. 1 pages 60 to 61." It has been also known that anthrone is produced by reducing anthraquinone with copper or iron and sulfuric acid and anthrone is converted to benzanthrone.
These conventional processes for producing anthrone have industrial disadvantages that expensive anthraquinone is used as a raw material and a large amount of powdery metal and a mineral acid which are expensive and not easily post-treated should be used and 7 to 10 times of a solvent to the raw material should be used.
The inventors have studied to produce anthrone without such disadvantages.